totm nov 2023 SpaceX Discussion Thread

[darthgently]

7 minutes ago, Terwin said:

Clearly every technical failure requires that we abandon all faulty technologies and start over with wood and bone tools!

Please don't exaggerate.  Wood and bone would obviously be augmented with bamboo, which is not ackshully wood.  So, we have that going for us. 

Fail slower!  It is crucial that by the time we have succeeded so much time has passed that the original planned mission has become completely obsolete; the finally produced craft having only political dog and pony use-cases remaining and zero practical applications

[magnemoe]

44 minutes ago, Terwin said:

Are you suggesting that yelling 'do better' on the internet after an experimental vehicle launch with no crew or payload experienced anomalies that did not injure any of the many many bystanders is an insufficient argument to tear-down and rebuild from scratch every involved agency and organization?!?!??!

Clearly every technical failure requires that we abandon all faulty technologies and start over with wood and bone tools!

No experience with bones outside the one inside me and in food.
But wooden shafts has lots of problems. 

The real problem is obviously that SpaceX tests in an place all can see. 

[tater]

1 hour ago, magnemoe said:

The real problem is obviously that SpaceX tests in an place all can see. 

Bezos' ranch in TX is literally 1000-2000X the size of starbase.

[SunlitZelkova]

9 hours ago, SOXBLOX said:

The FAA never applies lax standards. Just sayin'.

Just because they're making sure they know what they need to know about modern propellants doesn't mean we need an "independent study," whatever that is. 

Something something 737 MAX something something.

Not saying independent review is needed, just that the FAA is not that reliable.

[Nuke]

bureaucrats always overvalue their existence. ultimately they just want a job that involves no real work and no need to create anything, and they are willing to make life miserable for everyone else to get it. 

Edited May 23, 2023 by Nuke

[sevenperforce]

13 hours ago, magnemoe said:

14 hours ago, Terwin said:

Are you suggesting that yelling 'do better' on the internet after an experimental vehicle launch with no crew or payload experienced anomalies that did not injure any of the many many bystanders is an insufficient argument to tear-down and rebuild from scratch every involved agency and organization?!?!??!

Clearly every technical failure requires that we abandon all faulty technologies and start over with wood and bone tools!

No experience with bones outside the one inside me and in food.
But wooden shafts has lots of problems. 

I don't understand all of this insistence on using these new-fangled wooden tools. That's a fast way to get splinters, if you ask me. Fists and dirt clods were good enough for my grandpappy and they should be good enough for me.

[sevenperforce]

6 hours ago, SunlitZelkova said:

Something something 737 MAX something something.

Not saying independent review is needed, just that the FAA is not that reliable.

IIRC, the FAA's lapse over the 737 MAX came from delegating too many of the certifications to Boeing and just taking their word for it.

If the delayed effect of the Starship AFTS is considered a failure (and again, that's something I'm assuming, not something that's necessarily evident), then there's value in the FAA looking at whether a similar lapse was involved. Did the FAA simply trust SpaceX's assurances that the AFTS would produce an immediate RUD without verifying? Or was the delayed effect an unintended consequence of enhanced structural integrity that no one at SpaceX or the FAA could have anticipated? If the former, then it would be worthwhile for the FAA to look at its review process to see if it is unjustifiably delegating certifications in other areas. If the latter, then it falls into the "unknown unknown" category and increased oversight isn't going to make a lick of difference.

And ^^THAT^^ is how you properly handle root cause evaluation and mitigation of process lapse during a failure investigation. Not by demanding an undefined, ill-conceived "independent review" with no meaningful goals or realizable objectives.

[JoeSchmuckatelli]

I don't understand the hesitancy /resistance to oversight. It's not like this is rocket science, or anything.  We should absolutely trust the judgment of a politically appointed administrator to know what is in everyone's best interests. 

[Pthigrivi]

7 minutes ago, sevenperforce said:

IIRC, the FAA's lapse over the 737 MAX came from delegating too many of the certifications to Boeing and just taking their word for it.

If the delayed effect of the Starship AFTS is considered a failure (and again, that's something I'm assuming, not something that's necessarily evident), then there's value in the FAA looking at whether a similar lapse was involved. Did the FAA simply trust SpaceX's assurances that the AFTS would produce an immediate RUD without verifying? Or was the delayed effect an unintended consequence of enhanced structural integrity that no one at SpaceX or the FAA could have anticipated? If the former, then it would be worthwhile for the FAA to look at its review process to see if it is unjustifiably delegating certifications in other areas. If the latter, then it falls into the "unknown unknown" category and increased oversight isn't going to make a lick of difference.

And ^^THAT^^ is how you properly handle root cause evaluation and mitigation of process lapse during a failure investigation. Not by demanding an undefined, ill-conceived "independent review" with no meaningful goals or realizable objectives.

At the same time I don't think the FAA or the environmental review imagined SpaceX would be ejecting a few hundred tons of pulverized concrete over a 5m radius in a wildlife refuge. Im happy to see those plates go in and I hope they work. Seems like a lot of headaches and raised doubts could have been avoided by putting them in first. 

[darthgently]

I'm wondering if part of the delay of the FTS was underestimating how much stronger that flavor of SS is at cryo temps.  The (apparently) unexpected resilience of the craft while doing flips in thick air seems to somewhat support this possibility

[Kerwood Floyd]

48 minutes ago, sevenperforce said:

. . .the AFTS would produce an immediate RUD . . .

It seems you are forgetting what the U in RUD stands for. That RD is very much not U.  (j/k)

[sevenperforce]

55 minutes ago, JoeSchmuckatelli said:

I don't understand the hesitancy /resistance to oversight. It's not like this is rocket science, or anything.  We should absolutely trust the judgment of a politically appointed administrator to know what is in everyone's best interests. 

Eh, there's no resistance to oversight to be found here.

I've worked in the federal government -- specifically in the field of accident investigation, root cause evaluation, and process lapse mitigation. Specifically with methane, liquid hydrocarbons, and cryos, in fact. The feds on the ground performing certifications and evaluating process trees and double-checking industry work aren't political appointees. These offices are staffed with absolute nerd lifers whose entire personalities revolve around personal pet peeves that just happen to align with public safety. Bureaucracy moves slowly, but that can be a good thing in the world of safety, because political pressure doesn't often transfer downstream very well.

Where you see problems are political and administrative overrides, like Challenger. All of those people on the ground doing good work are useless when the higher-ups simply overrule their objections. If that happens, it's definitely a reason for Congressional or other oversight of the regulatory agency, but fortunately that sort of failure is quite open and notorious.

Calling for an "independent review" of something which still has not been shown to even constitute a failure doesn't seem like oversight; that seems like political posturing in its own right. I'm reminded of that scene from The Phantom Menace:

Chancellor Valorum: "The point is conceded. Will you defer to allow a commission to explore the validity of your accusations?"

Queen Amidala: "I will not defer. I've come before you to resolve this attack on our sovereignty now. I was not elected to watch my people suffer and die while you discuss this invasion in a committee!"

If there's an actual problem, then we should identify the problem, characterize the problem, and determine whether it was a lapse in oversight or an unknown unknown...not create an independent commission to tie things up endlessly with no actual goal or objective.

49 minutes ago, Pthigrivi said:

At the same time I don't think the FAA or the environmental review imagined SpaceX would be ejecting a few hundred tons of pulverized concrete over a 5m radius in a wildlife refuge. 

I haven't looked at the environmental review closely, but given that a pad RUD was one of the possible failures, I can't imagine what actually happened being WORSE than what the environmental review was prepared for.  If the whole stack had blown up on the pad it would have been a lot more destructive than what actually happened, and with a much bigger radius, too. The 2020 Beirut explosion had a yield of approximately 1.1 kilotons TNT equivalent and did this:

A Starship+Superheavy pad RUD would have a yield of at least three Beirut explosions and possibly up to nine Beirut explosions. Again, I cannot imagine that the pyroclastic pad launch (which blasted chunks of concrete as far as a kilometer but only sent fine particulate matter and dust significantly beyond that) was as bad as an RUD would have been. Dust and particulate matter certainly went beyond the expected debris field, which is cause for investigation, but that's already being investigated by the FAA.

49 minutes ago, Pthigrivi said:

Im happy to see those plates go in and I hope they work. Seems like a lot of headaches and raised doubts could have been avoided by putting them in first. 

You and me both. In hindsight it was more of a gamble than they thought, although I think it was more of a program/schedule gamble than a public safety gamble.

44 minutes ago, darthgently said:

I'm wondering if part of the delay of the FTS was underestimating how much stronger that flavor of SS is at cryo temps.  The (apparently) unexpected resilience of the craft while doing flips in thick air seems to somewhat support this possibility

Thick air, yes, but how thick?

38 km is certainly much lower in the atmosphere than the altitude where separation was intended to take place, but it is still MUCH higher than ordinary aerodynamic altitudes. At a speed of 500 meters per second and an air density of 0.41 g/m³, the dynamic pressure is 1.95% of the dynamic pressure on the SR-71 and a scanty 0.24% of the dynamic pressure on Falcon 9 at MaxQ. It's the equivalent of a semi-truck doing slow donuts while sliding across an icy parking lot at an average speed of 20 mph -- definitely out of the ordinary, but nothing you'd expect to crumple steel (at least not from aerodynamic forces).

Has there ever been an FTS activation at that altitude? Challenger blew up at around 15 km. Activation of FTS at 30+ km altitude might simply be something we've never experienced before.

Edited May 23, 2023 by sevenperforce
Clarify

[tater]

4 minutes ago, sevenperforce said:

A Starship+Superheavy pad RUD would have a yield of at least three Beirut explosions and possibly up to nine Beirut explosions. Again, I cannot imagine that the pyroclastic pad launch (which blasted chunks of concrete as far as a kilometer but only sent fine particulate matter and dust significantly beyond that) was as bad as an RUD would have been. Dust and particulate matter certainly went beyond the expected debris field, which is cause for investigation, but that's already being investigated by the FAA.

And this was the worst case assumption already internalized by FAA, hence exclusion for humans at however many km, so...

48 minutes ago, Pthigrivi said:

At the same time I don't think the FAA or the environmental review imagined SpaceX would be ejecting a few hundred tons of pulverized concrete over a 5m radius in a wildlife refuge. Im happy to see those plates go in and I hope they work. Seems like a lot of headaches and raised doubts could have been avoided by putting them in first. 

Um, yeah, they did. Their calculations assumed that a worst case might indeed happen, which of course would have been grossly worse than what happened just below the pad.

It's important to note that they are already working on all the issues, literally 24/7.

Pad/deluge/etc? Check.

FTS improvements? Check.

Spoiler

 

Engine reliability? Check (they are constantly working on that, it's just not as transparent to those of us watching from afar).

[mikegarrison]

3 hours ago, sevenperforce said:

IIRC, the FAA's lapse over the 737 MAX came from delegating too many of the certifications to Boeing and just taking their word for it.

The whole thing is more complicated than most people understand, but if the FAA had the ability to completely check all work done by all the aerospace manufacturers and all the airplane operators, they would need to have about the same number of employees as the whole industry put together.

The whole MAX thing is also not what most people understand, because there was a strong political push to find someone (Boeing) that they could blame for a much more complicated problem that they have no real answer for and don't want to address (namely that as planes get more and more automated, pilots stop remembering -- or in some cases even learning in the first place -- how to actually fly planes rather than how to tell the computer to fly the plane). And also a very serious lapse in safety culture at Boeing when they made hugely expensive guarantees to customers that no simulator training would be required for the MAX, and thus had a huge incentive to get the FAA to agree to that.

Those planes were completely flyable if the pilots had followed the checklists that they were supposed to have been trained to follow. Neither set of crew did.

The system should have been better designed to handle failures. The training should have been done. The pilots should have been better trained for when the systems they rely on stop working. The maintenance systems should have been better. Boeing should never have made guarantees that led to safety compromises. There were a *lot* of things that went wrong. Blaming it all on "the FAA delegated too much to Boeing" is over-simplifying to the point of being dangerous.

[sevenperforce]

54 minutes ago, mikegarrison said:

There were a *lot* of things that went wrong. Blaming it all on "the FAA delegated too much to Boeing" is over-simplifying to the point of being dangerous.

To be clear, I was saying that the FAA's lapse was over-delegation. The more serious lapses were within Boeing for sure. 

[steve9728]

Reviews from the gov and peers are the most objective review findings. But the problem is that the FAA is "not that reliable" in the eyes of the public, and there is no suitable bunch of peers who can match SpaceX.

[CBase]

3 hours ago, sevenperforce said:

Activation of FTS at 30+ km altitude might simply be something we've never experienced before.

Good point. Are there any kind of information whether it was some problem transmitting the FTS signal (maybe not redudant via starlink ?), processing the signal, igniting the charge or time / pressure for enough structural damage to rip it apart ? Would we have seen the charge going off on the video ? I mean on the test tank it looked pretty obvious. But if it wasn't going off, was dynamic pressure or integrity really an issue ? Or maybe antenna / processing ?

[Pthigrivi]

4 hours ago, sevenperforce said:

Eh, there's no resistance to oversight to be found here.

I've worked in the federal government -- specifically in the field of accident investigation, root cause evaluation, and process lapse mitigation. Specifically with methane, liquid hydrocarbons, and cryos, in fact. The feds on the ground performing certifications and evaluating process trees and double-checking industry work aren't political appointees. These offices are staffed with absolute nerd lifers whose entire personalities revolve around personal pet peeves that just happen to align with public safety. Bureaucracy moves slowly, but that can be a good thing in the world of safety, because political pressure doesn't often transfer downstream very well.

Where you see problems are political and administrative overrides, like Challenger. All of those people on the ground doing good work are useless when the higher-ups simply overrule their objections. If that happens, it's definitely a reason for Congressional or other oversight of the regulatory agency, but fortunately that sort of failure is quite open and notorious.

Calling for an "independent review" of something which still has not been shown to even constitute a failure doesn't seem like oversight; that seems like political posturing in its own right. I'm reminded of that scene from The Phantom Menace:

Chancellor Valorum: "The point is conceded. Will you defer to allow a commission to explore the validity of your accusations?"

Queen Amidala: "I will not defer. I've come before you to resolve this attack on our sovereignty now. I was not elected to watch my people suffer and die while you discuss this invasion in a committee!"

If there's an actual problem, then we should identify the problem, characterize the problem, and determine whether it was a lapse in oversight or an unknown unknown...not create an independent commission to tie things up endlessly with no actual goal or objective.

I haven't looked at the environmental review closely, but given that a pad RUD was one of the possible failures, I can't imagine what actually happened being WORSE than what the environmental review was prepared for.  If the whole stack had blown up on the pad it would have been a lot more destructive than what actually happened, and with a much bigger radius, too. The 2020 Beirut explosion had a yield of approximately 1.1 kilotons TNT equivalent and did this:

A Starship+Superheavy pad RUD would have a yield of at least three Beirut explosions and possibly up to nine Beirut explosions. Again, I cannot imagine that the pyroclastic pad launch (which blasted chunks of concrete as far as a kilometer but only sent fine particulate matter and dust significantly beyond that) was as bad as an RUD would have been. Dust and particulate matter certainly went beyond the expected debris field, which is cause for investigation, but that's already being investigated by the FAA.

You and me both. In hindsight it was more of a gamble than they thought, although I think it was more of a program/schedule gamble than a public safety gamble.

Thick air, yes, but how thick?

38 km is certainly much lower in the atmosphere than the altitude where separation was intended to take place, but it is still MUCH higher than ordinary aerodynamic altitudes. At a speed of 500 meters per second and an air density of 0.41 g/m³, the dynamic pressure is 1.95% of the dynamic pressure on the SR-71 and a scanty 0.24% of the dynamic pressure on Falcon 9 at MaxQ. It's the equivalent of a semi-truck doing slow donuts while sliding across an icy parking lot at an average speed of 20 mph -- definitely out of the ordinary, but nothing you'd expect to crumple steel (at least not from aerodynamic forces).

Has there ever been an FTS activation at that altitude? Challenger blew up at around 15 km. Activation of FTS at 30+ km altitude might simply be something we've never experienced before.

Haha truuuue. Yeah I wouldn't think the explosive velocity would be as high as ammonium nitrate but it would be plenty enough. Here's the pad after the N1 explosion. 



Edit: yeah detonation velocity peaking at 1800m/s vs 2700 for Ammonium nitrate. Still there's gonna be plenty of ejecta. 

Edited May 23, 2023 by Pthigrivi

[sevenperforce]

1 hour ago, CBase said:

5 hours ago, sevenperforce said:

Activation of FTS at 30+ km altitude might simply be something we've never experienced before.

Good point. Are there any kind of information whether it was some problem transmitting the FTS signal (maybe not redudant via starlink ?), processing the signal, igniting the charge or time / pressure for enough structural damage to rip it apart ? Would we have seen the charge going off on the video ? I mean on the test tank it looked pretty obvious. But if it wasn't going off, was dynamic pressure or integrity really an issue ? Or maybe antenna / processing ?

Starship+Superheavy, like Falcon 9, uses an AFTS. So there is no signal at all. Rather, the ship itself knows where it is and detonates itself if it flies outside of an acceptable corridor.

What happened with the Starship test launch was twofold. First, the range of acceptable launch profiles was quite high (since they had contingencies for thrust shortfalls) and so the acceptable corridor was extremely broad. Second, when it finally did fall outside of its acceptable corridor, it was at 38 km and tumbling slowly with relatively low aerodynamic stress. The FTS charges popped holes in the tanks, but there was enough residual head pressure in the tanks that they maintained structural integrity for almost a minute before finally imploding and then ripping apart.

Scott Manley has a video where he highlights the moment that the FTS charges go off and you can clearly see propellant spewing out while the tanks remain intact.

Had the AFTS fired lower in the atmosphere or while under significant acceleration (either due to gravity or thrust), the FTS charges would have caused immediate tank collapse and breakup. But being so high in the atmosphere while traveling relatively slowly was a different matter.

[Nuke]

they were using a tougher material than any previous rocket. as i understand it the fts was more or less an off the shelf model that was designed to rupture aluminum tanks. solving the problem seems just a matter of using a bigger explosive device. 

Edited May 23, 2023 by Nuke

[tater]

Weather later in the window actually looks better, but not sure about recovery zone weather.

 

[tater]

T-0 is now midnight, eastern.

[tater]

end of the window

[tater]

Window apparently goes til closer to 1:30 eastern

 

[tater]

live

standing down